\\[-1.8ex] Soil Heterogeneity & $-$0.421$^{**}$ & $-$0.430$^{**}$ & $-$0.497$^{**}$ & $-$0.463$^{*}$ \\ 
  & (0.172) & (0.172) & (0.243) & (0.238) \\ 
\\[-1.8ex] 
Observations & 5,585 & 5,585 & 2,038 & 2,038 \\ 
R$^{2}$ & 0.443 & 0.444 & 0.558 & 0.566 \\ 
